A PCB manufacturing method with special isolation line design

Abstract

The present invention application discloses a PCB manufacturing method with a special isolation line design. The PCB manufacturing method sets an isolation line area when designing the electroplating gold area by dry film exposure, and forms an isolation line on the negative film by local etching to isolate the electroplating gold area and the copper surface area, so that during the nickel-gold electroplating process, the liquid medicine is isolated by the isolation line and will not penetrate into the copper layer next to the nickel-gold, thereby solving the short circuit problem caused by the liquid medicine penetration; at the same time, because the entire pad is surrounded by nickel-gold in the PCB manufacturing method with a special isolation line design of the embodiment of the present invention, the overhang shedding problem and the short circuit problem caused by it are solved. The present invention can be widely used in the field of PCB manufacturing technology.

Description

Technical Field

[0001] The invention relates to the field of PCB manufacturing technology, in particular to a PCB manufacturing method with a special isolation line design. Background Art

[0002] The pads at the ball grid array (BGA) position of the printed circuit board (PCB) are used to solder components. In order to make the pads have good conductivity, solderability and reliability, nickel-gold electroplating is required on the pads during the production of the PCB board. In the common PCB nickel-gold electroplating process, the pads at this BGA position will have overhangs, and the overhangs are at risk of falling off during subsequent processing, resulting in a defect rate of more than 30%, and short circuit problems will occur during welding or mounting, which is less safe.

[0003] In order to prevent the short circuit problem caused by the pad overhanging, the traditional method is to surround the entire pad with nickel gold during the PCB manufacturing process, which includes the following process: first, the pattern of the area that needs to be electroplated with nickel gold is etched out, and then the nickel gold electroplating process is performed, so that the pad is surrounded by nickel gold, and there is no risk of overhanging and short circuit. However, during the nickel gold electroplating process, the solution will penetrate into the copper surface next to the nickel gold, causing large-scale short circuits or gold wire residue problems, and the defect rate is as high as 90%. Summary of the invention

[0004] In order to solve the above technical problems, an embodiment of the present invention provides a PCB manufacturing method with a special isolation line design.

[0005] The technical solution adopted in the embodiment of the present invention is:

[0006] A method for manufacturing a PCB with a special isolation line design includes the following steps:

[0007] Using dry film exposure to design an isolation line area and a gold-plated area on the film, the isolation line area is an area where an isolation line is set, the isolation line is used to isolate the copper surface area and the gold-plated area, and the gold-plated area is an area where nickel and gold are electroplated;

[0008] Forming the isolation line and the electro-gold region on the substrate by local etching;

[0009] The copper surface area is arranged on a side of the isolation line away from the electro-gold area;

[0010] Electroplating nickel-gold on the electro-gold area;

[0011] The isolation lines are etched to complete the PCB production.

[0012] As an optional implementation, the isolation line area surrounds the electroplated gold area.

[0013] As an optional implementation manner, the step of providing the copper surface area on a side of the isolation line away from the electroplated gold area includes:

[0014] Covering the target area with a dry film, wherein the target area includes an area outside the electroplating area;

[0015] Designing the copper surface area on the side of the isolation line away from the electro-gold area by dry film exposure;

[0016] Electroplating a copper layer and a tin layer in the copper surface area, wherein the tin layer is arranged on a side of the copper layer away from the bottom film;

[0017] The copper surface area is formed by local stripping of tin.

[0018] As an optional implementation manner, etching the isolation line includes:

[0019] The dry film on the isolation line is removed and then the isolation line is etched.

[0020] As an optional implementation, the step of designing the isolation line area and the electroplating gold area on the film by dry film exposure includes:

[0021] A negative film is used for dry film exposure, and the isolation line area and the electroplating gold area are designed on the negative film.

[0022] The PCB manufacturing method with a special isolation line design in the embodiment of the present invention sets an isolation line area at the same time when designing the electroplating gold area through dry film exposure, and forms an isolation line on the film through local etching to isolate the electroplating gold area and the copper surface area, so that during the nickel-gold electroplating process, the chemical is isolated by the isolation line and will not penetrate into the copper layer next to the nickel-gold, thereby solving the short circuit problem caused by the infiltration of the chemical; at the same time, because the entire pad is surrounded by nickel-gold in the PCB manufacturing method with a special isolation line design in the embodiment of the present invention, the overhang shedding problem and the short circuit problem caused by it are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of a PCB manufacturing method designed for a special isolation line according to an embodiment of the present invention;

[0024] Figure 2 Renderings of various regions of a PCB manufacturing method designed for special isolation lines according to an embodiment of the present invention.

[0025] Reference numerals: 201, isolation line area; 202, gold-plated area; 203, copper surface area. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0027] The terms "first", "second", "third" and "fourth" etc. in the specification and claims of the present application and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0028] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0029] The BGA pads of the PCB are used to solder components. In order to make the pads have good conductivity, solderability and reliability, nickel-gold needs to be electroplated on the pads during the production process of the PCB board. In the common PCB electroplating nickel-gold process, the pads at this BGA position will have overhang, and the overhang has the risk of falling off during the subsequent processing, resulting in a defect ratio of more than 30%, and will cause short circuit problems during welding or mounting, which is less safe. In order to prevent the short circuit problem caused by the overhang of the pad, the traditional method is to surround the entire pad with nickel-gold during the production process of the PCB, which specifically includes the following process: first etch out the pattern of the area where nickel-gold needs to be electroplated, and then perform the nickel-gold electroplating process, so that the pad is surrounded by nickel-gold, and there is no risk of overhang falling off and short circuit. However, during the nickel-gold electroplating process, the solution will penetrate into the copper surface next to the nickel-gold, resulting in large-area short circuits or gold wire residue problems, with a defect ratio of up to 90%. To this end, an embodiment of the present invention proposes a PCB manufacturing method with a special isolation line design, by simultaneously setting an isolation line area when designing the electroplating gold area during dry film exposure, and forming an isolation line on the film through local etching to isolate the electroplating gold area and the copper surface area, so that during the nickel-gold electroplating process, the solution is isolated by the isolation line and will not penetrate into the copper layer next to the nickel-gold, thereby solving the short circuit problem caused by the penetration of the solution; at the same time, since the entire pad is surrounded by nickel-gold in the PCB manufacturing method with a special isolation line design in the embodiment of the present invention, the overhang problem and the short circuit problem caused by it are solved.

[0030] like Figure 1 and Figure 2 As shown, the embodiment of the present invention provides a PCB manufacturing method with a special isolation line design, and the manufacturing method includes the following steps S101-S105:

[0031] S101, designing an isolation line area 201 and a gold-plated area 202 on a film by dry film exposure;

[0032] The isolation line area 201 is an area where isolation lines are set, and the isolation lines are used to isolate the copper surface area 203 and the electroplated gold area 102 . The electroplated gold area 202 is an area where nickel and gold are electroplated.

[0033] In the embodiment of the present invention, a negative film is used for dry film exposure, and an isolation line area 201 and a gold-plated area 202 are designed on the negative film.

[0034] S102, forming an isolation line and an electroplating gold region 202 on the substrate by local etching;

[0035] S103, setting a copper surface area 203 on a side of the isolation line away from the electroplated gold area 202;

[0036] In an embodiment of the present invention, the electroplated gold area 202 and the copper surface area 203 are isolated by an isolation line. Since the isolation line itself is insulated and not connected to the electroplated gold area 202 and the copper surface area 203 for conduction, the chemical will not penetrate into the copper surface area 203 when nickel-gold is subsequently electroplated in the electroplated gold area 202.

[0037] S103 can be further divided into the following steps S1031-S1034:

[0038] Step S1031, using a dry film to cover the target area;

[0039] The target area includes the area outside the electroplating area 202 .

[0040] Specifically, the embodiment of the present invention uses a dry film to cover the copper surface area 203 and the isolation line.

[0041] Step S1032, using dry film exposure to design a copper surface area 203 on a side of the isolation line away from the electroplated gold area 202;

[0042] Step S1033, electroplating a copper layer and a tin layer on the copper surface area 203, wherein the tin layer is arranged on a side of the copper layer away from the bottom film;

[0043] It can be understood that, since the isolation line is covered with a dry film in step S1031 , the isolation line will not be plated with copper and tin at this time.

[0044] In the embodiment of the present invention, the tin layer plays a role in protecting the copper layer.

[0045] Step S1034: forming the copper surface area by partially stripping tin.

[0046] S104, electroplating nickel-gold in the electroplated gold area 202;

[0047] It is understandable that, since the isolation line is covered with a dry film in step S1031, the isolation line will not be plated with nickel-gold at this time. And since the isolation line isolates the electroplated gold area 202 and the copper surface area 203, the solution will not penetrate into the copper surface area 203 when the electroplated nickel-gold is applied to the electroplated gold area 202.

[0048] S105, etching the isolation line to complete PCB production.

[0049] Specifically, the isolation line is etched after the dry film on the isolation line is removed. It is understandable that in step S105, the dry film covering other areas is removed at the same time, thereby completing the nickel-gold and copper plating, and etching the isolation line, completing the production of the PCB.

[0050] The PCB manufacturing method with a special isolation line design in the embodiment of the present invention (steps S101-S105) sets the isolation line area 201 at the same time when designing the electroplated gold area 202 by dry film exposure, and forms an isolation line on the film by local etching to isolate the electroplated gold area 202 and the copper surface area 203, so that during the nickel-gold electroplating process, the solution is isolated by the isolation line and will not penetrate into the copper layer next to the nickel-gold, thereby solving the short circuit problem caused by the penetration of the solution; at the same time, because the entire pad is surrounded by nickel-gold in the PCB manufacturing method with a special isolation line design in the embodiment of the present invention, the overhang shedding problem and the short circuit problem caused by it are solved.

[0051] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the described embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for manufacturing a PCB with a special isolation line design, characterized in that: The following steps are involved: The isolation line area and the electroplated gold area are designed on the film by dry film exposure, wherein the isolation line area is an area where an isolation line is set, and the isolation line is used to isolate the copper surface area and the electroplated gold area, and the electroplated gold area is an area where nickel and gold are electroplated; the isolation line area surrounds the electroplated gold area; Forming the isolation line and the electro-gold region on the substrate by local etching; The copper surface area is arranged on a side of the isolation line away from the electro-gold area; Electroplating nickel-gold in the electro-gold area; The isolation lines are etched to complete the PCB production.

2. The method for manufacturing a PCB with a special isolation line design according to claim 1, characterized in that: The copper surface area is arranged on a side of the isolation line away from the electroplating gold area, comprising: Covering the target area with a dry film, wherein the target area includes an area outside the electroplating area; Designing the copper surface area on the side of the isolation line away from the electro-gold area by dry film exposure; Electroplating a copper layer and a tin layer in the copper surface area, wherein the tin layer is arranged on a side of the copper layer away from the bottom film; The copper surface area is formed by local stripping of tin.

3. The method for manufacturing a PCB with a special isolation line design according to claim 2, characterized in that: The etching of the isolation line comprises: The dry film on the isolation line is removed and then the isolation line is etched.

4. The method for manufacturing a PCB with a special isolation line design according to claim 1, characterized in that: The method of designing the isolation line area and the electroplating gold area on the film by dry film exposure includes: A negative film is used for dry film exposure, and the isolation line area and the electroplating gold area are designed on the negative film.

Images